1. Field of the Invention
This invention relates to a connector in which terminals received respectively in terminal receiving chambers of a connector housing are retained against withdrawal by a retainer attached to the connector housing.
2. Description of the Related Art
In an ordinary connector, a terminal withdrawal prevention lance is formed within each terminal receiving chamber of a connector housing. When a terminal is inserted into the terminal receiving chamber of the connector housing (having such lances) from the rear side, first, the lance, while elastically deformed or bent, allows the insertion of the terminal, and when the terminal is further inserted into a predetermined position, the lance is restored from the elastically-deformed condition to become engaged with an engagement portion of the terminal, thereby preventing rearward movement of the terminal.
Also, it is a common practice to retain the terminal in a double manner against rearward movement by a retainer inserted into the connector housing from a side portion thereof.
In the case of forming the lances within the respective terminal receiving chambers, the molding of the lances is relatively difficult, and therefore there is known a connector of the type in which a front holder defining front ends of the terminal receiving chambers is attached to a connector housing, and the positions of the front ends of the terminals are determined by this front holder.
FIGS. 12 and 13 show a conventional connector disclosed, for example, in Patent Literature 1. FIG. 12 is a cross-sectional view showing a condition in which a retainer is held in a provisionally-retaining position, and FIG. 13 is a cross-sectional view showing an assembly-completed condition in which the retainer is moved into a completely-retaining position.
In this conventional connector, the retainer 120 and a front holder 130 having mating male terminal-receiving holes 132 are attached to a connector housing 100 having terminal receiving chambers 102. For assembling this connector, first, the front holder 130 is attached to a front end portion of a main portion 101 of the connector housing 100 having the terminal receiving chambers 102, and the retainer 120 is inserted into the main portion 101 of the connector housing 100 from a side portion of the connector housing 100, and is held in the provisionally-retaining position.
Then, in this condition, a terminal 150 is inserted into the terminal receiving chamber 102 from the rear side. As a result, a lance 103 formed within the terminal receiving chamber 102 is pressed and elastically deformed by the front end of the terminal 150, and when the terminal 150 is further inserted into a predetermined position, the lance 103 is restored from the elastically-deformed condition to become engaged with the terminal 150, thereby preventing the terminal 150 from rearward withdrawal.
Then, in this condition, the retainer 120 is moved into the completely-retaining position as shown in FIG. 13. As a result, an engagement portion 122 of the retainer 120 is engaged with a constricted portion, etc., of the terminal 150, thereby retaining the terminal 150 in a double manner against rearward movement.
FIG. 14 is a cross-sectional view of another conventional connector disclosed, for example, in Patent Literature 2 as seen from the front side.
In this conventional connector, terminal receiving chambers 202 are formed in a pillar-like main portion 201 of a connector housing 200, and a retainer 220 of a generally U-shaped cross-section is adapted to be fitted on the outer periphery of the pillar-like main portion 201. When the retainer 220 is held in a provisionally-retaining position, opening portions 222 of the retainer 220 are aligned respectively with the terminal receiving chambers 202, and therefore the retainer 220 allows the insertion of the terminals. When the retainer 220 is moved into the completely-retaining position, a retaining wall 221 of the retainer 220 intrudes into the terminal receiving chambers 202, and are engaged with the terminals, thereby preventing the withdrawal of the terminals.    Patent Literature 1: JP-A-2002-329548    Patent Literature 2: JP-A-2000-252000
In the conventional connectors, the retainer is provided only with the secondary terminal-retaining function, and in the case of providing the lances for primarily-retaining purposes, it is common to form these lances on the connector housing. However, these lances are formed within the respective terminal receiving chambers, and therefore in the case where the terminal receiving chambers have only small holes formed in their respective front ends, and therefore are almost closed at their front ends by the respective front walls, it is very difficult to mold these lances.
Therefore, in many cases, the front walls of the terminal receiving chambers have been formed or defined by the front holder 130 separate from the connector housing as in the conventional example of FIGS. 12 and 13 so that the lances 103 can be easily molded integrally on the connector housing 100.
However, when the front holder 130 is provided, there are encountered problems that the number of the component parts increases and that the time and labor for assembling the connector increase.
Furthermore, when the lances 103 are formed integrally on the connector housing 100, a resin material of an increased strength such as a glass-containing resin material can not be used for forming the connector housing since the lances need to have elasticity. As a result, there is encountered a problem that under high temperatures, the resin becomes soft, so that the connector will be affected by vibration.